Is the 2015 Porsche Cayman GTS the biggest threat to the 911?

On this episode of Ignition Jonny Lieberman tests the second generation Cayman in its most potent form yet. Packing 340 horsepower from an uprated 3.4 liter flat six, the Cayman GTS makes 15 horsepower more than the Cayman S and only 10 fewer than a base 911, while weighing hundreds of pounds less. With the additional power, is the Cayman GTS now a real threat to the 911, or is it simply a cynical marketing exercise from Porsche?